High speed magnetic counter

ABSTRACT

A resettable high speed magnetic counter includes a drive mechanism which permits the unidirectional advance of the counter&#39;&#39;s number wheels by retracting independently mounted verge drive arms. The reset button of the counter is adapted to spread the independent verge arms during the reset operation to thereby disengage the verge from the star wheel and enable the use of a direct driving engagement between the star wheel and the lowest order number wheel. The reset mechanism of the counter provides for delayed withdrawal of the reset fingers from the heart shaped reset cam after reset of the number wheels pending reengagement of the transfer pinions with the gears of the number wheels. The transfer pinions of the counter are suitably contoured to enable only transfer in a single rotatable direction with an interference lock preventing rebound inaccuracies. The magnet employs an E-shaped core limiting the flux path of the magnet to the core and flux plate while eliminating the clapper pivot from the flux path.

United States Patent 3,202,802 8/1965 Shoor 2,522,734 9/1950 Wood...

Inventors Appl. No.

Filed Patented Assignee HIGH SPEED MAGNETIC COUNTER 12 Claims, 9 Drawing Figs. US. Cl 235/92, 340/379 Int. Cl G06m 1/04 Field of Search 235/92 l 139; 340/378, 9; 335/297 References Cited UNITED STATES PATENTS 2,822,983 2/ I958 Sengebusch ABSTRACT: A resettable high speed magnetic counter includes a drive mechanism which permits the unidirectional advance of the counters number wheels by retracting independently mounted verge drive arms. The reset button of the counter is adapted to spread the independent verge arms during the reset operation to thereby disengage the verge from the star wheel and enable the use of a direct driving engage ment between the star wheel and the lowest order number wheel. The reset mechanism of the counter provides for delayed withdrawal of the reset fingers from the heart shaped reset cam after reset of the number wheels pending reengagement of the transfer pinions with the gears of the number wheels. The transfer pinions of the counter are suitably contoured to enable only transfer in a single rotatable direction with an interference lock preventing rebound inaccuracies.

235/92 The magnet employs an E-shaped core limiting the flux path 235/1 of the magnet to the core and flux plate while eliminating the 2,798,670 7/1957 Boyer 235/92 clapper pivot from the flux path.

56) 2% 743 24 /70 /a is a 34 j W2 641 272 l a 228 I 64 I 1 I; e782 I t '1 Z/fl i I i I; /96 220 2 l M .-/Z T l t 4" I 0 \T M4 P I g yt L g M6 I W 206 205 Patented May 18, 1971 4 Sheets-Sheet 1 INVENTORS JAMES P. BARRETT JOHN G. GAMBLE BY WW ATTORNEYS Patented May 18, 1971 4 Sheets-Sheet 2 FIG. 3

Patented May '18, 1911 4 She ets-Sheet 5 Patentd May 18, 1971 3,578,954

4 Sheets-Sheet 4 HIGH SPEED MAGNETIC COUNTER The present invention relates to high-speed magnetic counters and the like and is more particularly directed to a new and improved magnetic counter employing a stepped drive for advancing the counter in response to an electrical signal and a reset mechanism for resetting the counter prior to a subsequent counting operation.

An object of the present invention is to provide a new and improved high-speed magnetic counter which responds to an imbalanced condition created by an electrical impulse by permitting the immediate positive indexing of the counter without transmitting the magnet developed forces to the number wheels of the counter.

Another object of the present invention is to provide a new and improved magnetic counter wherein the counting speed can be controlled independently of the electrical signals received by the magnet thereby permitting higher operating speeds, greater accuracy of operation and synchronization between the mechanical and electrical systems of the counter to provide for both maximum electrical economy and prolonged, trouble-free operation.

An additional object of the present invention is to provide a new and improved magnetic counter of the type described employing a verge drive indirectly actuated by the operation of the electromagnet and provided with a pair of independent verge arms which are separately and adjustably powered whereby both of the verge arms are in independent engagement with the drive for the number wheels and adapted for being moved out of engagement with the drive during a resetting operation.

A further object of the presentinvention is to provide a new and improved magnetic counter which eliminates clapper bun and the fretting corrosion at the clapper pivot, as well as the operating fluctuations associated therewith, while at the same time synchronizing the mechanical and electrical systems of the counter mechanism to provide an increased operating life, improved reliability and a smooth and quiet counting operation.

Still another object of the present invention is to provide a counter employing an improved reset mechanism accompanied by withdrawal of the transfer pinions during the resetting operation, said improved reset mechanism preventing freewheeling of the counter wheels or inadvertent movement thereof during the resetting operation and particularly at the end thereof by providing for the delayed retraction of the reset fingers upon return contact of the transfer pinions with the number wheels of the counter.

A still further object of the present invention isto provide an improved reset mechanism for a verge driven electromagnetic counter which permits resetting of the counter with the power on, avoids the necessity of an extra pinion connecting the drive and unit wheel of the counter and at the same time obviates the clicking of the verge arm over the drive wheel during the resetting operation.

Still another object of the present invention is to provide a new and improved verge driven magnetic counter having an improved transfer pinion configuration, particularly adapted for use with counters capable of consecutive stepwise indexing, the pinion being provided with an improved tooth contour which reduces undesirable reverse movement of the counter wheels and the rebound impact associated with a half count stepwise indexing operation. Included in this object is the provision for a tooth contour which will provide for an intermediate locking position between the pinion and the driving gear so as to enable a smooth, unidirectional transfer between the counter wheels.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application which will be indicated in the appended claims.

In the drawings:

FIG. I is a front view, partially broken away and partially in section, of the improved counter of the present invention illustrating a portion of the resetdrive mechanism;

FIG. 2 is a sectional view taken along the line 2-2 of FIG. 1 with the housing removed;

FIG. 3 is a top view, partly broken away and partly in section, of the counter of FIG. 2;

FIG. 4 is a reduced side view of the counter of FIG. I mounted on a suitable support, with portions of the mounting member broken away;

FIG. 5 is a sectional view taken along the line 5-5 of FIG. 3;

FIG. 6 is a side view, partially broken away and partially in section, of the clapper mechanism of the counter showing the position of the mechanism before the magnet is activated;

FIG. 7 is a side view of a transfer pinion showing its relationship to the driving gear of a lower order number wheel of the counter;

FIG. 8 is a sectional view of the pinion taken along the line 88 of FIG.7; and

FIG. 9 is a view of the opposite side of the transfer pinion showing the driving gear portion of the pinion.

Referring now to the drawings in greater detail, wherein like reference characters indicate like parts throughout the several FIGS., there is shown an all purpose, adjustable, high-speed magnetic counter generally designated 10 which comprises a number wheel assembly 12, including a reset mechanism 14 for resetting the number wheels, and a drive assembly 16 for consecutively indexing or advancing the wheel assembly in response to an electrical signal received by the counter. The assemblies 12 and 16 are supported within an elongated, generally rectangular frame member 18 of sturdy construction which in turn is enclosed by front and rear housing or cover sections 20, 22, respectively, as best shown in FIG. 4 of the drawings.

The boxlike front section 20 of the housing includes a flat front plate portion 24 (FIG. I) provided with a generally rectangular, horizontally disposed, read-out window 26 extending across a substantial portion thereof for exposing a limited peripheral segment of each of the number wheels in the assembly 12. The front plate 24 additionally is provided with a relatively smaller, generally rectangular aperture 28 spaced to the side of the window 26 and vertically disposed adjacent one side of the housing 20 for accommodating the manually actuated reset button 30 of the reset mechanism 14. The frame 18 adjacent the reset button aperture 28 is provided with narrow top and bottom slots 32 for slidably receiving the key tabs 34 on the reset button 30 thereby facilitating smooth, nonwavering reciprocal operation of the button.

The generally rectangular, rear housing section 22, shown in FIG. 4, slidably receives the rearward end 38 of the counter within its forwardly opening cavity 40, locking it within the housing section 22 through the cooperative interengagement of one or more flexible detent tabs 42 of the housing with one or more central apertures 44 located in the top and/or bottom of the counter frame 18. The rear housing section 22 is further provided with an integral wall mounting portion 46 extending rearwardly of the cavity 40 and carrying a number of stepped locking tabs 48 which facilitate the mounting of the counter on a suitable support, such as the apertured supporting wall 50 depicted in FIG. 4. As can be appreciated the stepped configuration of the locking tabs 48 enables the counter to be securely held on walls of different thickness thereby giving added flexibility and adaptability to its utilization.

Referring particularly to FIG. 3 of the drawings, the wheel assembly 12 of the counter consists of a bank of spaced, coaxially aligned number wheels 52, including the lowest order number wheel 52' shown in section, rotatably mounted on a wheel supporting shaft 54 affixed to the sidewalls 56 of the counter frame I8. The number wheels 52 are positioned adjacent the front of the counter I0 for positioning a numeral, such as one of the consecutive numbers 0 through 9 located on the arcuate peripheral surfaces 58 of the wheels, in registry with the readout window 26 in the front plate of housing section 20. As illustrated, the lowest order number wheel 52 is provided with an elongated cylindrical hub portion 60 which supportably carries a star wheel 62 of the drive assembly 16, the star wheel being secured thereto for direct driving rotation therewith. Each of the rotatable number wheels are provided with an integral heart-shaped reset cam 64 extending radially outwardly from the wheel supporting shaft 54 and suitable peripheral gears for accomplishing a controlled sequential count transfer between the wheels through the operatively interconnected transfer pinions 66 rotatably mounted on the pinion supporting shaft 68. Thus, an integral two tooth driving gear sector 70 is provided on the left side of each number wheel, as viewed in FIG. 3, for driving a pinion 66 at the completion of each revolution of the number wheel, the pinion in turn indexing the adjacent higher order wheel through the wheel's integral driven gear 72 located on the right of the number wheels 52 as viewed in FIG. 3. As shown in FlGS. 2, 3 and S, the sidewalls 56 of the frame 18 are provided with longitudinally extending slots 74 for receiving the pinion-supporting shaft 68 and permitting reciprocable movement thereof away from and toward the bank of number wheels during a reset operating sequence. At least one end of the shaft 68 is suitably notched or keyed as shown at 76 to cooperate with the narrow slot 74 (FIG. in preventing undesirable rotation of the pinion supporting shaft as the pinions are moved out of engagement with the gears of the number wheels.

in accordance with the present invention the spaced, coaxially mounted transfer pinions 66 all are provided with a driven gear portion 78 (FIG. 7) and a driving gear portion 80 (FIG. 9) axially spaced and separated from portion 78 by the gear dividing ring 82. The driving gear portion 80 of each pinion is provided with conventional spur gear teeth 84 which intermesh with the driven gears 72 of the higher order number wheels for indexing or advancing the higher order wheels as an adjacent lower order number wheel completes a full revolution. The separated driven gear portion 78 of the pinion, on the other hand, is comprised of full and mutilated gear teeth, 86 and 88, respectively, which are configured to provide an elongated, tapered rear tooth face 90 with a greater portion of each tooth extending rearwardly of the tooths addendum radius line. As can be appreciated from FIGS. 3 and 7, the arcuate peripheral surface 58 of the number wheels will be interposed within the space provided by a mutilated pinion tooth 88 during nine-tenths of the lower order number wheel's rotation and will cooperate with the adjacent full pinion teeth 86 on each side of that space to provide a locking action which prevents rotation of the pinion during such rotation. However, as the leading face 92 of the two tooth driving gear sector 70 comes into contact with the trailing face 90 of a mutilated pinion tooth 88, it will act against the pinion tooth to initiate count transfer rotation thereof. At the same time, the recess or gullet 94 intermediate the teeth 96 of the two tooth driving sector 70 will come into registry with a full tooth 86 of the pinion. Continued rotation of driving sector 70 will then cause the full tooth 86 to rotate into the recess 94 as shown in P10. 7, and be driven by the sector 70 so as to produce the desired count transfer between the number wheels.

Thus, the driven gear portion 78 of the pinion intermeshes with and is driven by the two tooth driving gear sector 70 carried by the lower order number wheel. However, in ac cordance with the present invention, the top flat surface 98 of the rectangularly configured teeth 96 within the two tooth driving sector 70 coacts with the elongated trailing face 90 of the pinion teeth to provide a degree of interference which prevents reverse movement of the lower order number wheel by the pinion after a one-half count advance into the position illustrated in FIG. 7. In this manner there is provided a locked intermediate position during the count transfer operation. Advantageously, this one-way lock between the driving sector of the number wheels and the driven gear teeth of the pinions avoids any undesirable, inadvertent miscount due to the rebound frequently associated with a stepped drive.

Returning to FIGS. 1 through 3, the reset mechanism 14 associated with the wheel assembly 12 of the magnetic counter utilizes a heart cam reset arrangement which returns the number wheels to a zeroized condition when the reset button 30 is actuated. In accordance with the present invention the manually operated reset button 30 is a thin, generally rectangular member having on its innermost end a transverse, inwardly extending boss 100 carrying a spring mounting pin 102 which passes through the apertured shoulder 104 of the frame 18. A compression return spring 106 is mounted on the pin 102 between the frame shoulder 104 and the boss 100 for returning the button 30 to its normal rest position shown in P10. 3 after the number wheels have been reset. The thin, elongated reset button 30 is further provided with an integral rack 108 along a portion of its lower edge about midway along its length. As shown, the rack 108 meshes with and drives the reset pinion sector 110 rotatably mounted on the fixed reset shaft 112 for oscillatory rotation thereabout in response to the movement of the reset button, the reset pinion selector 110 having an integral elongated tubular hub 114. A transversely extending pinion yoke 116 mounted on the shaft 112 has one end thereof slidably carried by the hub 114 for limited rotation therewith. The yoke 116 is provided with a pair of upstanding, bifurcated, shaft-moving arms 118 which engage the pinion supporting shaft 68 and slide it along the slots 74 away from and toward the bank of number wheels. The transfer pinion yoke 116 is urged into constant frictional engagement with an upstanding shoulder 120 of the pinion sector 110 by the coiled compression spring 122 mounted over the hub 114 of the pinion sector. The yoke 116 is thus operatively interconnected with the manually operated reset button 30 through the friction clutch provided by the frictional engagement of the yoke 116 and shoulder 120, so that the transfer pinions will move .away from the number wheel bank as the reset button is pushed inwardly from its rest position and returned to reengage the bank as the button is returned to its rest position under the bias of its return spring 106. The friction clutch enables an ovcrtravel of the reset button after the shift of the pinion shaft has been accomplished, thus permitting the completion of the resetting operation.

During the resetting operation the pinions 66 are retracted to disengage the number wheels and individual reset fingers 124 (FlG. 2) are rotated into contact with the heart cams 64 associated with each number wheel, causing rotation of the wheels and alignment thereof in a zeroized condition. As best seen in FIGS. 1 and 2, a reset comb 126 supporting the integral, forwardly extending reset fingers 124 rotatably depends from the reset shaft 112 affixed to the counter frame 18 and extends transversely of the counter below the transfer pinions 66. The individual reset fingers 124 are provided with concave, cam-contacting tip portions 128 which act against the heart earns 62 to impart rotational motion to the wheels and bring them into a synchronized reset position. The reset comb 126 is rotatably powered by the reset button 30 through a connecting torsion reset spring 130 coiled about the shaft 112 and having one terminal leg 132 drivingly abutting the comb 126 for rotating it in a clockwise direction as viewed in FIG. 2. The opposite end 134 of the reset coil spring 130 is secured within a notch 136 of the spoollike reset sleeve 138 rotatably mounted on the shaft 112 and keyed to the coaxially mounted reset pinion hub 114 for rotation thereby. As shown in FIG. 1, the boss of frame 18 facilitates the independent washing of both the pinion yoke 116 and reset comb 126 on the shaft 112 so that the comb 126 may rotate independently of the yoke during the movement of the reset fingers 124 toward and away from the heart earns 64. Accordingly, as the reset button 30 is moved inwardly (to the right as viewed in FIG. 2) to load its return spring 106 and initiate a reset operating sequence, a clockwise rotational movement is imparted to the reset pinion sector 1? C and through the sector to the pinion yoke 116 and reset power spring 130. The rotation of the pinion yoke imparts rearward movement to the pinionsupporting shaft 68 mounted within the slots 74 causing the \pinions 66 to disengage the gears associated with the number wheels and permit rotational reset of the number wheels. Since the rearward movement of the pinions is substantially fully accomplished before the reset fingers 12A contact the heart earns 64, the friction clutch arrangement between the yoke 116 and the reset pinion shoulder 120 will permit the continued rotation or overtravel of the reset pinion sector 110 so that the reset fingers 1241 can effectuate the desired resetting operation. The reset comb 126 is thus driven in a clockwise direction by the reset pinion sector 1 through the reset spring 130 thereby moving the reset fingers 124 into contact with the heart earns 64 for rotatably camming the number wheels into a zeroized or reset condition.

As will be appreciated, the transfer pinions not only are withdrawn from engagement with the number wheels prior to the reset fingers acting against the individual heart cams for resetting the number wheels, but also are operative to immediately return and reengage their associated number wheels subsequent to a resetting thereof. Upon completion of the reset, the return spring 106 drives the released reset button 30 to the left, as viewed in FIG. 2, causing the reset pinion sector 110 in mesh with the rack 108 to rotate in a counterclockwise direction until the depending leg 140 on the reset button 30 comes into contact with the rearwardly protruding tapered shoulder 142 (FIG. 5) carried by the transfer pinion yoke 116, thereby assuring the full forward return of the transfer pinions into interrneshing engagement with the gears of the number wheels. The transfer pinion yoke 116 is, of course, carried by and with the reset pinion sector 110 as it moves in a counterclockwise direction, as viewed in FIG. 2, causing prompt engagement between the transfer pinions and the gears of the number wheels. However, the initial counterclockwise rotation of the reset pinion sector 110 does not effect immediate retraction of the reset fingers 124 from the heart earns 64. The reset drive spring 130 will tend to unwind slightly before releasing the reset comb 126 and will only thereafter permit the counterclockwise return of the fingers to the rest position of FIG. 2. Accordingly, the pinions 66 are permitted to reengage the gears of the number wheels prior to retraction of the resetting fingers, thereby preventing possible freewheeling of the number wheels as the reset fingers are retracted. Thus, it can be seen that the improved reset mechanism of the present invention assures -a prompt yet fully accurate reset of the number wheels without the possibility of the number wheels inadvertently moving out of their reset position.

Turning now to the electromagnetic drive assembly 16 for indexing the number wheels in response to an electrical signal received by the counter and particularly to FIGS. 3 and 6 of the drawings, a magnet designated 150 is mounted within the rearward section 38 of the frame 18 and consists of a tri-pole core member 152 of E-shaped configuration, and conventional electrical windings 154 circumscribing the center leg 156 of the core. The windings 154 are suitably connected to electrical inlet jacks 158 which protrude from the rear of the frame 18 and are suitably connected for receiving a count advancing electrical signal. It will be readily appreciated that the flat face 160 of the center leg 156 will constitute one pole face of the magnet while the faces 162 of the side legs 164 will make up the opposite pole face of the magnet.

A substantially flat, generally rectangular, flux plate 166 mounted on a nonconductive support 168 operates simultaneously against all the pole faces of the magnet as a clapper assembly and in accordance with the present invention provides a limited flux path between the center leg 156 and the pair of side legs 164 of the core. As best shown in FIGS. 3 and 6, the flux plate 166 is held within the support 168 by top and bottom retaining flanges 170 located on one side thereof and by the upstanding positioning bars 172 located on the other side of the clapper, the bars 172 being interposed between the center and side legs of the magnet to assist in the aligned oscillatory motion of the clapper assembly as the magnet is activated and deactivated. As clearly illustrated, the support 168 is rotatably mounted on the fixed shaft 174 for limited reciprocable or oscillatory movement toward and away from the pole faces. In accordance with the present invention it is required that only the generally rectangular flux plate 166 be metallic. The support 168 can be constructed of any suitable nonconductive material such as a durable, yet inexpensive plastic or the like. In view of this construction and the limited flux path associated therewith, the clapper assembly of the present invention advantageously eliminates the buzz frequently encountered in magnetic counters due to chattering or bouncing of the clapper and maintains an improved operating efficiency and reliability by eliminating the "fretting" corrosion heretofore found to occur when the clapper pivot was within the magnetic flux path.

The nonconductive support 168 is provided with an upwardly extending shoulder portion 176 and a flat, integral, reinforced verge arm retractor 178 which extends outwardly from the shoulder portion for moving the verge drive subassembly, designated generally by the numeral 190, in response to the activation and deactivation of the electromagnet. As best shown in FIGS. 3 and 6, the support 168 also carries on its shoulder 176 a rearwardly facing boss 180 for mounting one end of a clapper drive spring 182 adapted to constantly urge the clapper away from the-pole faces of the magnet. The compression drive spring 182 extends between the boss 180 on the support and the retaining ring 1840f the adjusting screw-186 mounted on the frame 18. It will be readily appreciated that the tension within the spring may be controlled by moving the screw 186 toward and away from the support to adjustably provide a sufficient force on the upstanding shoulder 176 for driving a verge arm out of contact with the ratchet star wheel 62 upon deactivation of the magnet without interfering with the movement of the clapper toward the electromagnet.

The verge drive subassembly 190 moved by the retractor 178 in response to the operation of the clapper toward and away from the magnet 150 comprises a pair of independent upper and lower verge arms 192 and 194, respectively, rotatably mounted on the pivot 196 which in turn is fixedly supported by the sidewall 56 of the frame 18. As best seen in FIG. 5, the lower verge arm 194 is comprised of an elongated, downwardly arcuate, tong-shaped pawl element 198 extending forwardly from the pivot 196 and terminating in a pawl foot 200 on its forward extremity for contacting and advancing the ratchet star wheel 62. Upstanding from the pivot end of the element 198 and located on opposite sides thereof is a pair of operating levers 202 disposed at an angle of about 80 relative to the element 198 and carrying at the free end portions thereof a connecting knob 204 against which the retrac tor 178 acts when the clapper moves away from the magnet under the bias of its drive spring 182 for driving the lower verge arm out of contact with the star wheel 62. A depending lug 206 projects downward from the element 198 below the pivot 196 and cooperates with a power drive spring 208 to constantly urge the lower verge arm 194 in a counter clockwise driving direction, viewed in FIG. 5. Additionally, the lug 206 is provided with the boss 210 which is contacted by the stop 212 adjustably supported by the frame 18 for limiting retracting movement of the arm 194.

The upper verge arm 192 is provided with an upwardly arched, elongated, tong-shaped pawl element 214 complementary to element 198 and terminating in a downwardly extending pawl foot 216 for drivingly contacting the ratchet star wheel 62. The upper verge element is rotatably mounted on the pivot196 intermediate the upwardly extending levers 202 of the lower verge arm and is provided with a stabilizing side lug 218 of generally L-shaped configuration which extends behind and around one of the levers 202 so that a leg portion 220 of the lug rests against the outer side 222 of the lever 202. The

upper verge arm is also provided with an operating lever 224 extending upwardly from the pivot 196 at an angle of about 60 relative to its respective element 214. The lever 224 is provided with a clapper contacting knob 226and a boss 228 for contacting the adjustable stop 230 and receiving the upper verge arm drive spring 232 which constantly biases the upper verge arm in a clockwise direction as viewed in FIG. 5.

As mentioned hereinbefore, the lowest order number wheel 52' supportably carries on its hub 60 a ratchet star wheel 62 which is secured thereto for rotation with the wheel 52' in response to the driving action of the verge subassembly 190. In view of the driving engagement between the star wheel and the lowest order number wheel, the counter of the present invention advantageously provides for the withdrawal of the verge drive arms from the star wheel during reset of the lowest order number wheel thereby obviating the necessity for a drive pinion therebetween. Accordingly, inwardly protruding lugs 240 are provided on the reset button 30 for acting against the armature 198, 214 during a resetting operation. Thus, as the reset button 30 is pushed inwardly, the lugs 240 contact the inner surfaces of the tong-shaped pawl elements spreading them apart and holding them out of engagement with the ratchet star wheel 62 to permit free rotational movement of the lowest order number wheel 52' in response to the action of a reset finger 124 against the heart cam 64 associated with the wheel. Therefore, clicking of the verge arms over the ratchet wheel during reset is avoided and resetting of the number wheels with the power on is facilitated.

From the foregoing detailed description of the verge drive subassembly it will be appreciated that if the verge arm levers are free from contact by the retractor on the clapper holder, the pawl foot of each arm will contact the ratchet star wheel under the influence of its respective drive spring, one of the pawls being fully positioned within a detent of the ratchet star wheel while the other is in a potential driving position. This is a condition of stable equilibrium since both arms of the verge drive exert a substantially equal force on the ratchet wheel, neither having a sufiicient driving force to rotate the wheel while its complementary arm is in contact therewith. However, when the retractor moves the detented pawl out of the detent position, an imbalance is created within the system which is immediately remedied by the opposite drive arm of the verge which drives from the rest position to a detent position in an attempt to restore balance to the system. Similarly, as the verge actuator releases the first verge lever and moves the second verge lever against the bias of its drive spring to drive the second detented pawl out of star wheel engagement and thereby cause a new imbalance in the opposite direction, the first verge arm will drive the ratchet wheel under the influence of its loaded driving spring. It can therefore be appreciated that the magnet developed forces are not transmitted directly to the star wheel. Rather, these forces act to lift the detented verge arm out of star wheel engagement, permitting the opposing spring loaded verge arm to drive the star wheel one-half count. Consequently, the magnet developed forces are utilized primarily to create an imbalanced condition within the system rather than create a positive direct driving force from the magnet to the number wheels. The countcr's maximum capability is adjustable depending upon the driving force of the verge arm power springs and is ultimately limited by the rigidity of the materials employed. Thus, by increasing the spring forces the speed of movement of the arms is increased. Below the level of material failure the maximum speed obtainable is then limited only by the life requirements of the materials and the speed per watt ratio deemed economical in the market place. It will, of course, be appreciated that to achieve maximum watt economy and a high counting accuracy the electrical characteristics of the electromagnetic subassembly must be set for the desired speed with the spring powered verge drive arms having a setting slightly higher than the maximum speed obtainable by the electromagnet at maximum rate of voltage.

As will be apparent to persons skilled in the art, various modifications and adaptations of the structure abovedescribed will become readily apparent without departure from the spirit and scope of the invention, the scope of which is defined in the appended claims.

We claim:

1. In a drive mechanism for producing unidirectional stepwise driving action, the combination of a pair of reciprocably mounted drive pawls alternately and independently movable in an operative direction and an opposite reciprocable direction, rotary means adapted to be successively indexed by each of the drive pawls in one angular direction upon alternate movement of the drive pawls in their operative direction, means for independently biasing each of the drive pawls in said operative direction, and pawl retracting means in releasable driving engagement with the pawls, said pawl retracting means being operative for alternately driving the drive pawls in their opposite direction and releasing the drive pawls to permit movement of the drive pawls in their operative direction under the bias of the biasing means to thereby successively impart unidirectional stepwise rotary motion to the rotary means.

2. The drive mechanism of claim 1 wherein the biasing means comprises independent biasing means for each of said drive pawls urging them in said operative direction, wherein the pawls are coaxially mounted and include forward driving elements engageable with the rotary means and rearward levers releasably engageable by the pawl retracting means to pivot the pawls in said opposite reciprocable directions out of engagement with the rotary means and against the bias of said independent biasing means.

3. In a magnetic counter having an electromagnet, a rotary counting device and a stepped drive for angularly advancing the counting device in response to an electrical signal received by the electromagnet, the improvement wherein the stepped drive includes a star wheel mounted for driving the counting device, clapper means movable toward and away from the electromagnet in response to the activation and deactivation thereof, and a pair of independently mounted reciprocable drive arms engageable with the star wheel for advancing the counting device including means for independently biasing each arm into engagement with the star wheel, the clapper means being in releasable operative engagement with the drive arms to alternately move the drive arms out of driving engagement with the star wheel against the bias of the biasing means and permit the advance of the counting device by the other drive arm.

4. The counter of claim 3 wherein the clapper means includes a drive arm retractor, the drive arms are coaxially mounted and include forward pawls engageable with the star wheel for imparting unidirectional rotary motion thereto and rearward levers engageable by the drive arm retractor for retracting the corresponding pawl from engagement with the star wheel and releasable by the drive arm for permitting driving engagement by the pawl under the bias of its biasing means.

5. The counter of claim 3 including reset means for resetting the counter, the reset means being provided with drive arm contacting portions for simultaneously moving both of the drive arms out of engagement with the star wheel during the resetting operation.

6. The counter of claim 5 wherein the drive arms include tong'shaped pawls and the reset means includes a reciprocating reset button with the arm contacting portions carried by the button for holding the pawls in a spaced nondriving condition during the resetting operation.

7. In a resettable counter having transfer pinions adapted to be shifted into and out of engagement with the number wheels during a resetting operation, a reset comb for resetting the number wheels upon the shift of the transfer pinions out of engagement and a reset button movable between a rest position and a resetting position for disengaging the pinions and actuating the reset comb, the combination including reset drive means operatively connecting the reset button and the comb, said drive means being operative for moving the transfer pinions out of engagement with the number wheels as the reset button is moved out of the rest position and being provided with delay means operativ: upon initial return movement of the button to the rest position to provide delayed retraction of the reset comb sufficient to permit reengagement between the transfer pinions and the number wheels prior to retraction.

8. The counter of claim 7 including a pinion shifting member responsive to the initial movement of the reset button 7 into and out of the rest position for shifting the pinions into and out of engagement with the number wheels, said shifting memberv engaging the drive means through a clutch permitting overtravel of the drive means upon full withdrawal of the transfer pinions and causing reengagement between the pinions and the number wheels upon the initial return movement of the reset button to the rest position.

9. The counter of claim 7 wherein the number wheels are each provided with a heart cam and the reset comb includes reset fingers movable into engagement with the individual heart cams for resetting the number wheels, the delay means being effective for holding the reset fingers in contact with the cams while the drive means moves the pinions into reengagement with the number wheels.

10. The. counter of claim 7 wherein the delay means includes a drive spring in driving engagement with the reset comb and connected with the reset button whereby initial return movement of the button causes relaxation of the drive spring without retraction of the reset comb.

11. In a counter wherein count advancing transfer is accomplished by the driving interengagement between the driving gear of a lower order number wheel and the driven gear teeth of a transfer pinion, the improvement of preventing reverse transfer wherein the pinion has a driving portion and an axially spaced driven portion including the driven gear teeth and the driven gear teeth of the pinion provide sufficient clearance relative to the intermeshing driving gear of the number wheel to permit driving engagement by the driving gear while preventing driving engagement by the driven gear teeth of the pinion.

12. In a counter wherein count advancing transfer is accomplished by the driving interengagement between the driving gear of a lower order number wheel and the driven gear teeth of a transfer pinion, the improvement of preventing reverse transfer wherein the counter employs a stepwise count advancing drive, the driving gear teeth of the number wheel have a generally rectangular sectional configuration and the driven gear teeth of the pinion are configured to exhibit a larger tooth portion rearwardly of their addendum radius and an elongated trailing face effecting nondriving interference with the driving gear teeth and a no-back lock between steps of the count. 

1. In a drive mechanism for producing unidirectional stepwise driving action, the combination of a pair of reciprocably mounted drive pawls alternately and independently movable in an operative direction and an opposite reciprocable direction, rotary means adapted to be successively indexed by each of the drive pawls in one angular direction upon alternate movement of the drive pawls in their operative dirEction, means for independently biasing each of the drive pawls in said operative direction, and pawl retracting means in releasable driving engagement with the pawls, said pawl retracting means being operative for alternately driving the drive pawls in their opposite direction and releasing the drive pawls to permit movement of the drive pawls in their operative direction under the bias of the biasing means to thereby successively impart unidirectional stepwise rotary motion to the rotary means.
 2. The drive mechanism of claim 1 wherein the biasing means comprises independent biasing means for each of said drive pawls urging them in said operative direction, wherein the pawls are coaxially mounted and include forward driving elements engageable with the rotary means and rearward levers releasably engageable by the pawl retracting means to pivot the pawls in said opposite reciprocable directions out of engagement with the rotary means and against the bias of said independent biasing means.
 3. In a magnetic counter having an electromagnet, a rotary counting device and a stepped drive for angularly advancing the counting device in response to an electrical signal received by the electromagnet, the improvement wherein the stepped drive includes a star wheel mounted for driving the counting device, clapper means movable toward and away from the electromagnet in response to the activation and deactivation thereof, and a pair of independently mounted reciprocable drive arms engageable with the star wheel for advancing the counting device including means for independently biasing each arm into engagement with the star wheel, the clapper means being in releasable operative engagement with the drive arms to alternately move the drive arms out of driving engagement with the star wheel against the bias of the biasing means and permit the advance of the counting device by the other drive arm.
 4. The counter of claim 3 wherein the clapper means includes a drive arm retractor, the drive arms are coaxially mounted and include forward pawls engageable with the star wheel for imparting unidirectional rotary motion thereto and rearward levers engageable by the drive arm retractor for retracting the corresponding pawl from engagement with the star wheel and releasable by the drive arm for permitting driving engagement by the pawl under the bias of its biasing means.
 5. The counter of claim 3 including reset means for resetting the counter, the reset means being provided with drive arm contacting portions for simultaneously moving both of the drive arms out of engagement with the star wheel during the resetting operation.
 6. The counter of claim 5 wherein the drive arms include tong-shaped pawls and the reset means includes a reciprocating reset button with the arm contacting portions carried by the button for holding the pawls in a spaced nondriving condition during the resetting operation.
 7. In a resettable counter having transfer pinions adapted to be shifted into and out of engagement with the number wheels during a resetting operation, a reset comb for resetting the number wheels upon the shift of the transfer pinions out of engagement and a reset button movable between a rest position and a resetting position for disengaging the pinions and actuating the reset comb, the combination including reset drive means operatively connecting the reset button and the comb, said drive means being operative for moving the transfer pinions out of engagement with the number wheels as the reset button is moved out of the rest position and being provided with delay means operative upon initial return movement of the button to the rest position to provide delayed retraction of the reset comb sufficient to permit reengagement between the transfer pinions and the number wheels prior to retraction.
 8. The counter of claim 7 including a pinion shifting member responsive to the initial movement of the reset button into and out of the rest position for shifting the pinions intO and out of engagement with the number wheels, said shifting member engaging the drive means through a clutch permitting overtravel of the drive means upon full withdrawal of the transfer pinions and causing reengagement between the pinions and the number wheels upon the initial return movement of the reset button to the rest position.
 9. The counter of claim 7 wherein the number wheels are each provided with a heart cam and the reset comb includes reset fingers movable into engagement with the individual heart cams for resetting the number wheels, the delay means being effective for holding the reset fingers in contact with the cams while the drive means moves the pinions into reengagement with the number wheels.
 10. The counter of claim 7 wherein the delay means includes a drive spring in driving engagement with the reset comb and connected with the reset button whereby initial return movement of the button causes relaxation of the drive spring without retraction of the reset comb.
 11. In a counter wherein count advancing transfer is accomplished by the driving interengagement between the driving gear of a lower order number wheel and the driven gear teeth of a transfer pinion, the improvement of preventing reverse transfer wherein the pinion has a driving portion and an axially spaced driven portion including the driven gear teeth and the driven gear teeth of the pinion provide sufficient clearance relative to the intermeshing driving gear of the number wheel to permit driving engagement by the driving gear while preventing driving engagement by the driven gear teeth of the pinion.
 12. In a counter wherein count advancing transfer is accomplished by the driving interengagement between the driving gear of a lower order number wheel and the driven gear teeth of a transfer pinion, the improvement of preventing reverse transfer wherein the counter employs a stepwise count advancing drive, the driving gear teeth of the number wheel have a generally rectangular sectional configuration and the driven gear teeth of the pinion are configured to exhibit a larger tooth portion rearwardly of their addendum radius and an elongated trailing face effecting nondriving interference with the driving gear teeth and a no-back lock between steps of the count. 